Section III. Digitigrada

In this section of the Carnivora the heel is raised above the ground, with the whole or the greater part of the metacarpus and metatarsus, so that the animals walk more or less completely on the tips of the toes (fig. 424, C). No absolute line, however, of demarcation can be drawn between the Plantigrade and Digitigrade sections of the Carnivora, since many forms (e.g., Mustelidae and Viver-ridae) exhibit transitional characters, and it has even been proposed to place these in a separate section, under the name of Semi-plantigrada. Moreover, the Mustelidae and Melidae are so nearly allied that they can with difficulty be kept apart.

The first family of the Digitigrada is that of the Mustelidae or Weasels, including a number of small Carnivores, with short legs, elongated worm-like bodies, and a peculiar gliding mode of progression (hence the name of Vermiformes, sometimes applied to the group). The dental formula of Mustela proper is:

i

3 - 3

; c

1 - 1

; pm

4 - 4

; m

1 - 1

=

38.

3 - 3

1 - 1

4 - 4

2 - 2

In the nearly-allied genus Putorius (fig. 430) there is a prae-molar less above and below.

Among the best known of the Mustelidae are the common Weasel (Putorius vulgaris), the Polecat (Putorius foetidus), and the Ferret (Putorius furo), the last being usually regarded as an albino variety (now permanent) of one of the Polecats. It is really an African form, but it has been long domesticated in Europe. Nearly-allied types are the Ermine or Stoat (Putorius erminea), and the Minks (P. vison and P. lutreola) of North America and Europe. Among the species of Mustela proper may be mentioned the Pine-marten (M. martes) and Stone-marten (M. foina) of Europe and Asia, the Pekan or "Fisher" (M. Pennantii) of North America, the true Sable (M. zibellina) of northern Asia, and the American Sable (M. Americana). The Mustelidae are of commercial importance as yielding beautiful and highly-valued furs, the skins of the Sable, Ermine, Black Mink, and Pekan, being specially sought after.

Fig. 430.   Skull of the Polecat (Putorius foetidus).

Fig. 430. - Skull of the Polecat (Putorius foetidus).

Almost all the Weasels have a very disagreeable odour, produced by the secretion of greatly-developed and modified sebaceous glands, placed in the neighbourhood of the anus, and known as the anal glands. In this respect, however, the nearly-allied genus Mephitis, comprising the American Skunk, is facile princeps. The Skunk is a pretty little animal, with a long bushy tail, and when unmolested it is perfectly harmless. If pursued or irritated, however, it has the power of ejecting the secretion of the anal glands to a greater or less distance with considerable force. The odour of this secretion is so powerful and persistent that no amount of washing will remove it from a garment, and its characters are said to be of the most intensely disagreeable description.

Nearly related to the family of the Mustelidae. are the Otters (Lutra), distinguished by the possession of webbed feet adapted

Fig. 431.   Skull of common Otter (Lutra vulgaris), viewed from one side.

Fig. 431. - Skull of common Otter (Lutra vulgaris), viewed from one side.

(After Coues.) for swimming. The body is long, the legs short, and the tail long, stout, and horizontally flattened. The common Otter (Lutra vulgaris, figs. 431, 432) is a native of Britain, frequenting the banks of streams and lakes. It lives upon fish, and is highly destructive to salmon. A closely-allied form is the American Otter (Lutra Canadensis). In the Sea-otters (Enhydris) the tail is very short. They are found on both sides of the North Pacific, and yield a very valuable fur, being much more strictly aquatic in their habits than the ordinary Otters. Besides Enhydris, a species of Sea-otter belonging to the genus Nutria is found on the shores of North and South America, ranging from California to Chili.

Fig. 432.   Under view of the skull of the common Otter. (After Coues.)

Fig. 432. - Under view of the skull of the common Otter. (After Coues.)

The second family of the Semi-plantigrade Carnivores is that of the Viverridae, the Civets and Genettes. They are all of moderate size, with sharp muzzles and long tails, and more or less striped, or banded, or spotted. The dental formula of Viverra is:

i

3 - 3

; c

1 - 1

; pm

4 - 4

; m

2 - 2

=

40.

3 - 3

1 - 1

4 - 4

2 - 2

The upper carnassial (the 4th praemolar) and the lower carnassial (the 1st molar) have cutting edges (fig. 433); while both the upper molars and the last lower molar have tubercu-late crowns. The canines are long, sharp, and pointed. The tongue is roughened by numerous prickly papillae. The claws are semi-retractile, and the pupils can contract, on exposure to light, till they resemble a mere line. In most of their characters, therefore, the Civets are much more highly carnivorous than are any of the preceding families, and they approach in many respects very close to the typical group of the Digitigrada (viz., the Felidae), having especially very close affinities with the Hyaenas. Many of the species of the family are furnished with anal glands, which secrete the peculiar fatty substance known as "civet." All the Viverridae belong to the Old World.

Section III Digitigrada 525Fig. 433.   Dentition of the Civet cat (Viverra civetta). The upper figure shows the upper jaw, the lower figure gives the lower teeth.

Fig. 433. - Dentition of the Civet-cat (Viverra civetta). The upper figure shows the upper jaw, the lower figure gives the lower teeth.